Cordless Phone Buying Guide

Frequency and bandwith

Megahertz (MHz) and Gigahertz (GHz) are measurements that refer to radio frequency (RF) signals used by cordless phones and a lot of other electronic gadgets. So many devices use RF that cordless phones experience signal interference if too much activity happens at once. Wireless networks, microwave ovens, wireless video game controllers and baby monitors, to name a few, all use or interfere with RF signals. The first step in choosing the cordless phone that’s right for you is evaluating the level of RF usage in your home and neighborhood.

Common cordless phone RF ranges are 2.4 GHz and 5.8 GHz.  The 900Mhz cordless phones that were once standard have been discontinued because of interference problems. Most household interference affects 2.4GHz cordless phones, but they’re still a good—and inexpensive—choice if you live in a rural area, far from neighbors and RF interference. In urban and suburban settings, it’s best to choose a 5.8GHz cordless phone. If your budget is too limiting for this, look for a 2.4GHz cordless phone that is wireless network friendly. These cordless phones are designed to work with some wireless networks without interference.

If you’ve got the budget, you’ll get a minimum of interference with the latest RF technology, Digital Enhanced Cordless Telecommunication (DECT), which operates on the 1.9GHz band that the Federal Communications Commission has reserved for voice.

Analog versus digital

If you’ve ever picked up the neighbor’s baby monitor, someone else’s conversation or the police scanner on your cordless phone, then you’re familiar with the interception and security issues analog cordless phones experience. This tendency toward interference makes analog cordless phones a poor choice for urban and other densely populated areas.

Digital cordless phones are more secure and less prone to interference than analog cordless phones, but some users report that voices sound hollow or tinny as compared to the voice quality on analog devices. If you want a digital cordless phone with enhanced security, look for models with Digital Spread Spectrum (DSS), which digitize your voice over a slightly longer range and offer added security with a cipher key that scrambles conversations across frequencies. To further reduce interference, look for cordless phones with Frequency Hopping Spread Spectrum (FHSS), which transmits and receives signals on several channels at once. If a signal is poor on one frequency, the clear signal on another frequency will compensate.

DSS is most often found on 5.8GHz cordless phones, but some 2.4GHz phones offer it as well. DECT cordless phones use their own encryption and authentication methods to ensure privacy. If you choose a digital cordless phone, be sure it’s listed as a digital phone and not “phone with digital,” which is an analog cordless phone with some digital features, such as an answering machine.

Battery life

Most cordless phones offer users approximately three to five days of standby time, which is the amount of time the cordless will maintain a charge. Battery life during usage ranges from 5 to 16 hours, depending upon the manufacturer. Look for cordless phones with Li-ion or Ni-MH batteries to provide the best battery life. NiCad batteries tend to develop “charge memory” that becomes smaller over time until you’re forced to replace them. No matter which kind of battery you choose, check the cost of replacement batteries (usually between $15 and $40) and that they’re readily available. Batteries tend to last 1 to 2 years.

Features

Standard cordless phone features include caller ID, speed dial or a built-in phone book, backlit keys and/or display, paging and speakerphone. Advanced cordless phone features are plentiful, but more often than not, the more features you want, the more the cordless phone will cost.

Advanced cordless phone features include multiple lines, full-color displays (similar to those on cell phones) and speakerphones built into the charger base that let you to make and receive calls without the handset. If you don’t have voicemail through your service provider or other answering machine, choose a model with a built-in answering machine to save on space. People who multitask while they’re on the phone should look for models with belt clips or holsters and a headset for mobile, hands-free talking.

If you don’t have a corded phone elsewhere in your house, look for cordless phones that offer a corded phone on the primary base unit. In the event of a power outage, you’ll still be able to make and receive calls provided your phone service remains intact.

Innovations

The latest advances in cordless telephone features include VoIP-compatible models (Voice Over Internet Protocol) that don’t require an adaptor to connect the phone to the Internet. Some cordless phones offer Skype features to make placing and receiving calls over your computer even easier. For cell phone users who have spotty reception or service at home, perhaps the most exciting advancement are DECT cordless phones that work with your cell phone so your cell calls can be sent directly to your cordless phone handset.

Multi-handset cordless phone systems are a hot trend. Most manufacturers include a second handset with a separate base unit and offer you the option of adding more handsets as needed.  The primary base unit requires a phone jack, but the expandable handsets can be plugged into any power source. Look for multi-handset cordless phones if you have a large home or if you’re outfitting a small office. Most multi-handset cordless phone systems allow you to call between handsets via an intercom function, do conference-calling with multiple handsets taking place in a call or place a call on hold so that someone can pick up from another handset.

Need to know more?

• What is DECT?
  http://www.dectweb.com/dectforum/aboutdect/whatis.htm
• Why Cordless VoIP Phones are a Good Idea
  http://blogs.zdnet.com/ip-telephony/?p=1221
• How Cordless Phones Work
  http://www.howstuffworks.com/cordless-phone.htm